1. Field of the Invention
The invention concerns a device for adjusting the “vertical” position of a blow mandrel of a blow molding machine provided to be moveable up and down on a blow mandrel carrier associated with the machine frame of the blow molding machine, upon which blow mandrel carrier at least two blow mandrels are provided, which blow into die cavities of a blow mold provided below the blow mandrel carrier, wherein the blow mandrel during entry into the blow mold both defines the gauge or calibration of a neck region of the mold hollow body as well as causes the separation of plastic material protruding outwards from the neck, wherein the separation occurs by pinching the protruding material by means of a ring shaped cutting edge of the respective blow mandrel, which during penetration into the blow mold lie against a conical counter surface of the blow mold and by this contact along a circular line of the conical surface causes the cutting off of the projecting plastic material, wherein the blow mandrel is provided axially displaceable in a receptacle mounted fixed to the carrier and is adjustable, for example, by means of an adjusting screw, into a suitable position for the pinching off the protruding material.
2. Description of the Related Art
In known adjusting devices of this type, there is provided for the height adjustment of the injection mandrel a set screw in clamping engagement with a threaded blow mandrel receptacle and a retaining or securing screw extending axially there-through and for its part in clamping engagement with the blow mandrel body, which are respectively used as set screw and counter screw. This type of adjustment is only possible with a “resting” machine, since the process requires the loosening of the respective counter screw from the set screw, of which the readjustment and subsequent renewed necessary countering or locking demands substantially more time than available during the duration of a conventional blow cycle. The consequence of requiring this type of out-of-operation phase in order to carry out the adjustment is associated at least with substantial loss of material since, in the case that the extrusion operation of the extruder of the machine is continued in order to maintain thermal stability of the machine, a substantial amount of plastic material is lost, or, in the case that the extruder is also taken out of operation, in that restart period of time until a “thermal” process stability is again achieved, much waste is produced. In addition to this, the taking of the machine out of operation results in economic losses. The likelihood of requiring this type of adjustment increases with the increasing number of blow mandrels provided on a carrier and is otherwise also high in the so-called set up phase, when production is to begin with a newly installed tool.